[PATCH] mtd: Add sync/unblank function to mtdoops

From: Richard Purdie
Date: Tue Jul 10 2007 - 15:34:22 EST


mtdoops wasn't ensuring data was flushed to flash in crash situations
after recent changes in mainline kernels as tracking the
oops_in_progress variable was no longer enough. We can use the "unblank"
console call as a sync call to tell us to write out the buffer though.

Therefore add a sync function to mtdoops and call this when console
unblank events occur.

Signed-off-by: Richard Purdie <rpurdie@xxxxxxxxxxxxxx>

Index: linux/drivers/mtd/mtdoops.c
===================================================================
--- linux.orig/drivers/mtd/mtdoops.c 2007-07-10 20:01:34.000000000 +0100
+++ linux/drivers/mtd/mtdoops.c 2007-07-10 20:23:09.000000000 +0100
@@ -271,40 +271,50 @@ static void mtdoops_notify_remove(struct
flush_scheduled_work();
}

-
-static void
-mtdoops_console_write(struct console *co, const char *s, unsigned int count)
+static void mtdoops_console_sync(void)
{
- struct mtdoops_context *cxt = co->data;
+ struct mtdoops_context *cxt = &oops_cxt;
struct mtd_info *mtd = cxt->mtd;
- int i, ret;
+ size_t retlen;
+ int ret;

if (!cxt->ready || !mtd)
return;

- if (!oops_in_progress && cxt->writecount != 0) {
- size_t retlen;
- if (cxt->writecount < OOPS_PAGE_SIZE)
- memset(cxt->oops_buf + cxt->writecount, 0xff,
+ if (cxt->writecount == 0)
+ return;
+
+ if (cxt->writecount < OOPS_PAGE_SIZE)
+ memset(cxt->oops_buf + cxt->writecount, 0xff,
OOPS_PAGE_SIZE - cxt->writecount);

- ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
+ ret = mtd->write(mtd, cxt->nextpage * OOPS_PAGE_SIZE,
OOPS_PAGE_SIZE, &retlen, cxt->oops_buf);
- cxt->ready = 0;
- cxt->writecount = 0;
+ cxt->ready = 0;
+ cxt->writecount = 0;

- if ((retlen != OOPS_PAGE_SIZE) || (ret < 0))
- printk(KERN_ERR "mtdoops: Write failure at %d (%d of %d"
- " written), err %d.\n",
- cxt->nextpage * OOPS_PAGE_SIZE, retlen,
- OOPS_PAGE_SIZE, ret);
+ if ((retlen != OOPS_PAGE_SIZE) || (ret < 0))
+ printk(KERN_ERR "mtdoops: Write failure at %d (%d of %d written), err %d.\n",
+ cxt->nextpage * OOPS_PAGE_SIZE, retlen, OOPS_PAGE_SIZE, ret);

- ret = mtdoops_inc_counter(cxt);
- if (ret == 1)
- schedule_work(&cxt->work);
+ ret = mtdoops_inc_counter(cxt);
+ if (ret == 1)
+ schedule_work(&cxt->work);
+}
+
+static void
+mtdoops_console_write(struct console *co, const char *s, unsigned int count)
+{
+ struct mtdoops_context *cxt = co->data;
+ struct mtd_info *mtd = cxt->mtd;
+ int i;
+
+ if (!oops_in_progress) {
+ mtdoops_console_sync();
+ return;
}

- if (!oops_in_progress)
+ if (!cxt->ready || !mtd)
return;

if (cxt->writecount == 0) {
@@ -344,6 +354,7 @@ static struct console mtdoops_console =
.name = "ttyMTD",
.write = mtdoops_console_write,
.setup = mtdoops_console_setup,
+ .unblank = mtdoops_console_sync,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &oops_cxt,

-
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